Textile products for use in the clothing industry and the processes for their manufacture are developing rapidly. Since about 1985, semi-permeable products have been developed which are impermeable to water, but which let carbon dioxide and water vapor pass through; such products are labelled as breathable. These products protect the user from rain and wind while remaining perfectly comfortable to wear.
To this end, products in which a semi-permeable layer or film is directly applied to a cloth are known. Other products are also known in which an insert forms a semi-permeable barrier in clothes. Breathable inserts are generally made by gluing a semi-permeable film to a textile support. Such inserts can, in addition to modifying the impermeable properties of a garment, serve their usual purpose of altering the mechanical properties of a garment. Inserts are generally attached to a textile substrate by use of a discontinuous thermofusible polymer.
All of the prior art techniques for producing "breathability" are relatively restricting, and the presence of a semi-permeable layer makes it difficult to control the appearance, feel and hang of the textile.
Moreover, the semi-permeable film has mechanical properties (elasticity, resistance to traction, and shrinkage due to temperature or maintenance) that are different from those of the textile support to which it is generally attached. These differences in behavior directly affect the interface between the textile support and the film and quickly lead to localized tearing of the adhesive and may lead to it becoming completely detached.
In order to remedy these drawbacks, it has been envisioned to directly use a microporous polymer film or layer to make up an insert. Nonetheless, such films or layers do not have sufficient mechanical resistance.
In U.S. Pat. No. 4,863,788, to Bellairs et al., a thin microporous membrane formed of polyvinylidene fluoride (PVDF) was attached to one surface of a woven nylon taffeta. While the fabric was waterproof and breathable, the product was stiff due to polymer solution striking completely through the fabric, and due to the relative inflexibility of the microporous membrane in comparison to the fabric. Further, the membrane delaminated completely from the fabric after only 5 wash and dry cycles. The membrane surface was easily damaged by abrasion, causing the film-coated fabric to lose its waterproof character. Therefore, Bellairs et al. turned to the use of a polyurethane foam to attach a thin microporous membrane to one surface of a textile to convert the textile to a waterproof and breathable textile product. For example, a nylon taffeta textile was converted to a waterproof and breathable fabric product by first adhering a thin polyurethane foam layer (@ 0.1 mm) to one surface of the fabric without allowing penetration of the foam into the fabric or textile substrate; then, a PVDF microporous film layer was formed on the surface of the thin open celled polyurethane foam layer. The resulting coated fabric exhibited no stiffness or strikethrough of the polymer, and samples withstood twenty wash and dry cycles with no delamination. The samples also exhibited excellent resistance to abrasion and damage of the microporous layer.
Nevertheless, the textile product of Bellairs et al. is difficult to produce, and the thin microporous layer, once damaged, loses its waterproofness. Therefore, it is desired to produce a waterproof and breathable textile product which will be sufficiently flexible and which will retain its waterproof properties even if the surface of the waterproof and breathable coating is slightly damaged, and yet which can be produced in a simpler manner than prior art breathable inserts.
Thus, objects of the present invention include providing an insert which does not have the drawbacks exhibited by prior art waterproof and breathable textiles, producing a textile whose properties can be controlled and which is pleasing to the touch and to the eye, and which fulfills the conditions required for use of such a textile product in the clothing industry, i.e. sufficient mechanical resistance, resistance to dry cleaning and washing, resistance to abrasion and rubbing which occur when clothes are worn.